Acute Effect of Air Pollution on Respiratory Complaints, Exhaled NO and Biomarkers in Nasal Lavages of Allergic Children during the Pollen Season

Abstract

During 2 months of the pollen season, the acute and putative adjuvant effect of traffic-related air pollution on respiratory health was investigated in children sensitised to grass pollen or house dust mite (HDM). Respiratory complaints were objectified via measurement of exhaled NO and inflammatory mediators in nasal lavage (NAL). During the study children, skin prick negative (n = 31) or positive to grass pollen (n = 22), HDM (n = 34) or grass pollen + HDM (n = 32), kept a daily diary on respiratory symptoms, and NAL and exhaled air was sampled twice a week. The level of air pollutants and pollen was monitored continuously. Like children sensitised to HDM, those sensitised to pollen reported respiratory complaints (shortness of breath, itchy eyes or blocked nose) more frequently than non-sensitised children during (but not before) the pollen season; the respiratory complaints of sensitised children were independent of the pollen level. In addition, exposure to increased levels of PM₁₀ induces ‘shortness of breath’ in pollen- and HDM-sensitised children, whereas ozone induces a blocked nose in HDM-sensitised children. Combined exposure to PM₁₀ + pollen and O₃ + pollen induces a blocked nose in both HDM-sensitised children and children sensitised to pollen + HDM. Significant positive associations were found between eNO and the levels of NO₂, CO, PM_2.5 and pollen in both sensitised and non-sensitised children. At the start of the pollen season, the NAL concentration of eosinophils and ECP in pollen-sensitised children was increased compared to winter, but their levels were not further affected by increased exposure to pollen or air pollution. In conclusion, during the pollen season, sensitised children continuously report a high prevalence of respiratory complaints which coincides with increased levels of upper and lower airway inflammatory markers. No additional pro-inflammatory effect of air pollution was observed, which indicates that air pollution does not facilitate allergen-induced inflammatory responses.

Air Pollution and Increased Levels of Fractional Exhaled Nitric Oxide in Children with No History of Airway Damage

“…As a result, FeNO is generally considered to be a reliable noninvasive marker of airway inflammation. Exhaled nitric oxide was used as a biomarker in numerous studies to evaluate the effects of air pollution (Adamkiewicz et al, 2004;BarrazaVillarreal et al, 2008;Delfino et al, 2006;Fischer et al, 2002;Franklin et al, 2000;Giroux et al, 2001;Holguin et al, 2007;Jansen et al, 2005;Koenig et al, 2003Koenig et al, , 2005Mar et al, 2005;Nickmilder et al, 2003;Steerenberg et al, 1999Steerenberg et al, , 2001Steerenberg et al, , 2003Van Amsterdam et al, 1999a, 1999b. Results of these studies supported the idea that outdoor air pollution may lead to airway inflammation (Holguin, 2008).…”

“…Previously, FeNO-correlated exposure to fine particles was assessed outdoors by fixed stations (Adamkiewicz et al, 2004;Barraza-Villarreal et al, 2008;Delfino et al, 2006;Jansen et al, 2005;Mar et al, 2005;Steerenberg et al, 2001Steerenberg et al, , 2003Van Amsterdam et al, 1999a) or through objective assessments at the community level Koenig et al, 2003Koenig et al, , 2005 or in indoor environments Koenig et al, 2003Koenig et al, , 2005. Only three recent studies found significant associations between FeNO levels with measurements of personal PM (Delfino et al, 2006;Koenig et al, 2003Koenig et al, , 2005.…”

“…Most previous studies involved asthmatic individuals as they constitute a susceptible group. Only three studies considered exposure of non-asthmatic children at the city level (Barraza-Villarreal et al, 2008;Holguin et al, 2007;Steerenberg et al, 2003), with one significant finding (Steerenberg et al, 2003). During the pollen season, Steerenberg et al (2003) observed a positive association between FeNO levels assessed by monitoring stations and exposure to PM 2.5 among non-asthmatics.…”

Allergic Rhinitis and its Impact on Asthma (ARIA) 2008*

“…Acute effects due to the outdoor exposure to certain gases/ fumes and PM have not been sufficiently studied with regards to nasal symptoms. The few available studies inconsistently suggest an increase in rhinitis symptoms or consultations for allergic rhinitis during peaks of pollution (686)(687)(688). Pollution and meteorological factors are closely related to complaints of nonallergic, noninfectious perennial rhinitis patients (689).…”

Indoor- and Outdoor-Derived Contaminants in Urban and Rural Homes in Ottawa, Ontario, Canada

“…15 In the case of pollen-sensitive individuals, increased symptoms have been seen for both particulate 16 and gaseous 17 traffic-derived pollutants compared with individuals who were not pollen sensitive. Steerenberg et al 18 report increased symptoms in response to air pollution for children sensitized to house dust mite allergen. Laboratory animal studies indicate that particulate traffic pollutants act as an adjuvant for allergens.…”